Reincarnated as a Dog with System - Chapter 92: Mana Core formation

In a modern world where cultivators need a place to cultivate or vent their boredom, there are private businesses that set up instance dungeons with the aid of technology and cultivation magic to enable cultivators to train and commoners to experience the life of cultivation. They are called dungeon suppliers.
Xie Jin's one and only dream was to be a dungeon supplier and when his only relative passed away, the relative's inheritance gave him a plot of land and surprisingly, a 'System' Module which the relative had previously used.
With the help of the system, Xie Jin decided to pursue his dream of becoming the number one dungeon supplier.

A river song, triggered a legend of the rivers and lakes.
Tian Zun’s life motto: “My sword is the truth.”
Shen Lang’s life motto: “To serve people with morality, those who are dissatisfied are dead.”

- Description from uukanshu (translated)

As Mingguang Sect’s esteemed Immortal Master, Yi Ning had never experienced much heartbreak and suffering. He had always expected his life to be smooth-sailing, and was only waiting to ascend before marrying his disciple with whom he shared mutual affection.

However, he had never expected that on a rainy night, his disciple brought back a childhood friend.

They were close and intimate, to the point… of sharing a bed.

Standing before the bed where they were entwined, Yi Ning’s heart was as cold as sunken ice. He had wanted to end it all cleanly and straightforwardly, yet had never expected that his disciple not only wanted his childhood friend, but wanted his Shizun too.

His disciple shattered his spiritual core and laid down a hex, throwing him into the main hall to await nightfall to consummate their relationship.

Just as he had fallen into despair and wanted to end his life, he unexpectedly discovered a strange book. The book detailed his life, and the him it described, from beginning to end, was nothing more than a tool used to satisfy his disciple’s desire to conquer, lowly and wretched as a cultivation furnace.

Yi Ning’s head spun, and his heart gave birth to a strong hatred. He dragged his wrecked body to the back of the mountain and released the Demon Venerable Yan Xuan, who he had personally sealed nine years ago.

In return for undoing the seal, Yan Xuan would aid him in escaping.

After the man heard the reason why, he leaned against the wall and smiled with a hint of mockery. Yi Ning had thought he was going to ridicule him for having deserved it, being betrayed by an ingrate who bit the hand that fed him.

Yet, what he never expected was for Yan Xuan to reach out and tug him into his embrace, and the words that left his mouth were instead:

“You fool, I’ll help you take revenge.”

After this, he killed all those who wronged him, and cradled him close to his heart.

He wants to shatter your cultivation and mangle your limbs, to turn you into a bird in a cage, free for him to humiliate.

Yet, with this lowly and dirty heart of mine, I want to pull you from the swamp and cut down the heavens for you.

- Description from Novelupdates